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Understanding antibody-based SARS-CoV-2 immunity in hematologic malignancy (HM) patients following infection is crucial to inform vaccination strategies for this highly vulnerable population. This cross-sectional study documents the anti-SARS-CoV-2 humoral response and serum neutralizing activity in 189 HM patients recovering from a PCR-confirmed infection. The overall seroconversion rate was 85.7%, with the lowest values in patients with lymphoid malignancies or undergoing chemotherapy. Therapy-naive patients in the “watch and wait” status were more likely to seroconvert and display increased anti-s IgG titers. Enhanced serum neutralizing activity was observed in the following SARS-CoV-2-infected HM patient groups: (i) males; (ii) severe COVID-19; and (iii) “watch and wait” or “complete/partial response”. The geometric mean (GeoMean) ID50 neutralization titers in patients analyzed before or after 6 months post-infection were 299.1 and 306.3, respectively, indicating that >50% of the patients in either group had a neutralization titer sufficient to provide 50% protection from symptomatic COVID-19. Altogether, our findings suggest that therapy-naive HM patients mount a far more robust immune response to SARS-CoV-2 infection vs. patients receiving anti-cancer treatment, raising the important question as to whether HM patients should be vaccinated before therapy and/or receive vaccine formats capable of better recapitulating the natural infection.

Indolent non-Hodgkin lymphomas (iNHL) are a heterogeneous group of pathologies characterized by a prolonged natural history and good response to treatment. They also have a tendency to relapse, in some cases with a worse prognosis. One of the main objectives in the newest clinical trials is to identify patients at high risk of relapse. This cannot be accomplished using only clinical prognostic scores. Detection of minimal residual disease (MRD) is effective in evaluating long-term disease response, with a strong and independent predictive value that was demonstrated in large cohorts of patients. Analysis of MRD allows patient stratification based on the risk for relapse; therefore, different therapeutic programs can be designed based on the response characteristics. This tailored therapy is already happening in current clinical trials. Limits imposed by traditional PCR-based tools are being overcome due to new molecular biology techniques like droplet digital PCR and next generation sequencing. Although these techniques are not yet standardized, they will likely increase the reliability and ensure broad applicability of MRD detection in future years.

Tumor cells in chronic lymphocytic leukemia (CLL) are more prone to apoptosis when cultured ex vivo, because they lack prosurvival signals furnished in vivo via B-cell receptor (BCR)-dependent and -independent pathways. This study compared the susceptibility of unmutated (UM) and mutated (M) CLL B cells to spontaneous apoptosis and prosurvival signals. UM CLL B cells showed a significantly higher rate of spontaneous apoptosis than M CLL B cells. Nuclear factor-kB (NF-kB) was rapidly inactivated, and B-cell leukemia/lymphoma 2 (Bcl-2) expression progressively down-regulated in the UM CLL B cells. CD40-Ligand, interleukin-4 and stromal cells significantly improved their viability and partially recovered Bcl-2, but not NF-kB expression. Peripheral blood mononuclear cells also offered protection of UM CLL B cells, and recovered both NF-kB and Bcl-2 expression. T cells, rather than nurse-like cells, were responsible for protecting UM CLL B cells by means of cell-to-cell contact and soluble factors. Despite their more aggressive features, UM CLL B cells are more susceptible to spontaneous apoptosis and depend from environmental prosurvival signals. This vulnerability of UM CLL B cells can be exploited as a selective target of therapeutic interventions.

Background and aims. In CLL, TL has been associated to outcome. However a larger patient sample and an analysis on a blinded validation series are required to fully establish the independent prognostic value of TL and to define its impact on prognostic subgroups defined according to established predictors. These issues have been addressed on a CLL learning cohort and validated on an independent blinded cohort, overall accounting for 401 CLL patients. Also, we have tested TL as a risk factor of Richter’s Syndrome (RS), an extremely severe event that most of the currently available biomarkers fail to predict. Methods. The learning series (LS) included 191 patients from the university of Torino (UT), while the blinded validation series (BVS) included 210 patients from University of Eastern Piedmont (UEP). TL was assessed on PBMC collected at diagnosis by Southern blotting and no biological or clinical feature of BVS patients was available to the laboratory performing the analysis. Detailed clinical history, clinical parameters at diagnosis as well as VH-mutational status, cytogenetics, CD38 expression and Zap-70 were available for the vast majority of patients and employed together with TL as covariates for multivariate survival analysis. Results. The two series showed no differences for any clinical and biological features except age that was slightly higher in the BVS series. Also TL distribution was similar in the two series (median TL 6024 and 5959 bp respectively). By applying ROC analysis and Youden’s index to the LS we identified a cut-off point of 5000bp segregating 26% (104/401) of patients in the high-risk subgroup. TL was a powerful and independent outcome predictor for both TFS (24.6 vs 73 months p65 years, p65 years (p=.004), Binet stage B-C (p Conclusions. These results demonstrate that TL is a powerful independent predictor of multiple outcome events in CLL and contributes to refine the prognostic assessment of CLL when utilized in combination with other prognostic markers. We thus recommend a more widespread use of this biomarker in CLL. Figure Figure

B-CLL patients with resistant/relapsed disease or adverse prognostic factors at presentation are suitable for alternative treatments. In the present pilot study we investigated a novel intensive chemo-immunotherapy approach for high-risk, fludarabine pretreated patients. Ten patients with resistant/relapsed, advanced stage BCLL were included. Age was 37-60 yr (median 53). All but one had an unmutated IgVH status. The treatment schedule included debulking with two DHAP courses followed by alemtuzumab (30 mg, eight doses), followed by peripheral blood progenitor cell (PBPC) mobilization with intermediate/high-dose cyclophosphamide and by autografting after high-dose mitoxantrone+L-Pam. The DHAP-alemtuzumab combination was highly effective. Eight patients out of 10 responded to DHAP, with a single complete remission. Following alemtuzumab, the number of overall responses increased to nine, and the complete remissions to five. After alemtuzumab PB double-positive clonal CD5+/CD19+ lymphocytes dropped, with median purification rate 99.95%. Owing to poor PBPC mobilization, only five patients underwent autografting, and three of these experienced post-graft recurrence. The six patients entering complete remission were free of disease 3-23 mo after study entry, and three of them were still in remission at 3, 7, and 22 mo. However, molecular evaluation regularly revealed persistence of minimal residual disease, both in all PBPC collections tested and in post-treatment follow-up samples. The use of DHAP/alemtuzumab appears useful to re-induce disease remission in relapsed/refractory, high-risk B-CLL patients. However, the addition of autograft was not usually feasible and of questionable clinical use. Other strategies should thus be considered for remission maintenance.

The purpose of the study was to compare telomere length (TL) in peripheral blood progenitor cells (PBPC) collected after two tightly spaced high-dose (hd) chemotherapy courses. We assessed 37 previously untreated lymphoma patients undergoing a hd-chemotherapy program with autografting. They sequentially received hd-cyclophosphamide (CY) and hd-Ara-C, both followed by PBPC harvesting. Both post-CY and post-Ara-C harvests were assessed for TL by Southern blot analysis. In 12 patients, the assay was also performed on purified CD34+ cells. All patients displayed high PBPC mobilization following both hd-CY and hd-Ara-C. In all but one patient, TL was shorter in PBPC collected after Ara-C compared to CY: 7226bp (range: 4135-9852) vs 8282 bp (range 4895-14860) (P0.0001). This result was confirmed on CD34+ cells. Platelet recovery in patients receiving post-Ara-C PBPC was significantly slower compared to those receiving post-CY PBPC. In conclusion, (i) administration of tightly spaced hd-chemotherapy courses induces marked telomere shortening on harvested PBPC; (ii) engraftment kinetics seem slower, with delayed platelet recovery, in patients autografted with PBPC suffering marked TL erosion; (iii) long-term follow-up is required to verify whether PBPC with shortened telomeres display defective engraftment stability and/or risk of secondary leukemia; (iv) TL evaluation is advisable whenever new mobilization procedures are developed.